Guo Baihe, Wang Yanlin, Shen Xin, Qiao Xiaolei, Jia Li, Xiang Jun, Jin Yan
College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China.
Materials (Basel). 2020 Feb 15;13(4):877. doi: 10.3390/ma13040877.
In this paper, a silica aerogel support was prepared by two-step sol-gel method, and the active component KCO was supported on the support by wet loading to obtain a modified potassium-based CO adsorbent. As the influences of reaction conditions on the CO capture characteristics of modified potassium-based adsorbents, the reaction temperature (50 °C, 60 °C, 70 °C, 80 °C), water vapor concentration (10%, 15%, 20%), CO concentration (5%, 10%, 12.5%, 15%), and total gas flow rate (400 mL/min, 500 mL/min, 600 mL/min) were studied in a self-designed fixed-bed reactor. At the same time, the low-temperature nitrogen adsorption experiment, scanning electron microscope, and X-ray diffractometer were used to study the microscopic characteristics of modified potassium-based adsorbents before and after the reaction. The results show that the silica aerogel prepared by the two-step sol-gel method has an excellent microstructure, and its specific surface area and specific pore volume are as high as 838.9 m/g and 0.85 cm/g, respectively. The microstructure of KCO loaded on the support is improved, which promotes the CO adsorption performance of potassium-based adsorbents. The adsorption of CO by potassium-based adsorbents can be better described by the Avrami fractional kinetic model and the modified Avrami fractional kinetic model, and it is a complex multi-path adsorption process, which is related to the adsorption site and activity. The optimal adsorption temperature, water vapor concentration, CO concentration, and total gas volume were 60 °C, 15%, 12.5%, and 500 mL/min, respectively.
本文采用两步溶胶-凝胶法制备了二氧化硅气凝胶载体，并通过湿浸渍法将活性组分KCO负载在该载体上，得到改性钾基CO吸附剂。作为反应条件对改性钾基吸附剂CO捕集特性的影响，在自行设计的固定床反应器中研究了反应温度（50℃、60℃、70℃、80℃）、水蒸气浓度（10%、15%、20%）、CO浓度（5%、10%、12.5%、15%）和总气体流速（400 mL/min、500 mL/min、600 mL/min）。同时，利用低温氮气吸附实验、扫描电子显微镜和X射线衍射仪研究了反应前后改性钾基吸附剂的微观特性。结果表明，两步溶胶-凝胶法制备的二氧化硅气凝胶具有优异的微观结构，其比表面积和比孔容分别高达838.9 m/g和0.85 cm/g。负载在载体上的KCO的微观结构得到改善，促进了钾基吸附剂的CO吸附性能。钾基吸附剂对CO的吸附能用Avrami分数动力学模型和改性Avrami分数动力学模型较好地描述，且是一个复杂的多路径吸附过程，这与吸附位点和活性有关。最佳吸附温度、水蒸气浓度、CO浓度和总气体体积分别为60℃、15%、12.5%和500 mL/min。
